Description: (Applicant's Description) UPCI's laboratory Animal Facility is located in the Biomedical Science Tower and is an AAALAC-approved facility. It is managed by the Department of Laboratory Animal Resources, University of Pittsburgh, headed by Paul H. Bramson, D.V.M. The Facility, which opened in 1991, was developed in response to the needs of the UPCI and other investigators whose research requires virus-free animals for their research. Many of the studies of the UPCI investigators concern the immunologic responses to tumors and often require long-term maintenance of mice and rats, including nude mice, for tumor development and experimental manipulations. Therefore, it is essential that the animals have a stable environmental background, without interruption by periodic and unpredictable microbial infections. Veterinary medical support staff is provided in conjunction with the University's Laboratory Animal Resources. The overall veterinary staff includes five veterinarians, one board certified veterinary pathologist, five animal health technicians and a histopathology technician. Most histopathology and microbiology can be performed in-house. A stringent program for monitoring the health and potential exposure to infectious agents of the animals housed has been implemented. Sentinel animals are placed in each animal room and are sampled quarterly to assess background pathology and viral antibody profiles. In addition to the direct supervision of the facility by Dr. Bramson and the Facility supervisor, policies involving other issues are dealt with by the Laboratory Animal Facility Committee, chaired by Dr. Candace S. Johnson, Deputy Director for Basic Research, and comprised of all investigators who house animals in the facility. This committee has formulated the Policies Regulating Use of the BST Animal Facility, and meets as needed, to discuss problems or issues related to the facility. Policies have been written to cover the purchasing, sources and health monitoring of the laboratory animals.